POS1388 CLINICAL RELEVANCE OF ANTI-SSA ANTIBODIES: A SINGLE-CENTRE EXPERIENCE
Authors: C. Mazeda, S. P. Silva, R. Monteiro, R. Aguiar, A. Barcelos
Journal: Annals of the Rheumatic Diseases (2022)

Background Anti-Ro/SSA antibodies are directed against different proteins of intracellular small ribonucleic acid (RNA)-protein complexes, Ro60 (60 kDa) and Ro52 (52 kDa) and are the most frequently detected autoantibodies in patients´ sera. The clinical associations with antibodies to the Ro60 protein is well documented and includes systemic lupus erythematosus (SLE) and Sjögren syndrome (SS). [1]The presence of anti-Ro52 antibodies has been reported in a large variety of diseases, such as neoplastic diseases or viral infections [1, 2]. Objectives The aim of this study was to analyze the clinical relevance and the disease phenotype of patients with anti-Ro52 and/or anti-Ro60 autoantibodies in a single portuguese tertehospital. Methods Retrospective and descriptive study included all patients screened for anti-nuclear antibodies (ANA) in the database of the immunology laboratory of our Hospital between 2017 and 2021. Only adult patients (≥ 18-years-old) with positive anti-Ro52 and/or Ro60 were included in the study and divided into three groups: group 1 – Ro52+/Ro60-, group 2 – Ro52+/Ro60+ and group 3 – Ro52-/Ro60+. The presence of ANA was tested by indirect immunofluorescence (threshold of positivity established at titer 1/160) and further screened for anti-extractable nuclear antigen (ENA) antibodies. Socio-demographic and clinical data were collected. Descriptive analysis was performed, p-value≤0.05 was statistically significant. Results Among 1210 patients, 277 were positive for the antibody anti-Ro52 and/or Ro60. Most of the patients included were women (79.8%) with a mean age of 58.87±16.12. Immune-mediated rheumatologic diseases were diagnosed in 173 (62.5%) patients, while 104 (37.5%) had non-rheumatologic disease. About 38.6% were exclusively anti-Ro52 positive, 30.3% of patients were anti-Ro60 positive alone and 31% tested positive for both. The clinical data of the patients in these three groups is represented in Table 1. In each of the three groups, the most frequent pattern was nuclear fine spleckled (AC-4). In group 2, SS was the most frequent diagnosis (46.5%), followed by SLE (19.6%). Regarding ANA titers, a higher amount was observed in this group (p&lt;0.05). The most frequently associated autoantibodies were anti-La (15.1%). In group 3, the diagnosis of SS was the most frequent (23.8%) followed by undifferentiated connective tissue disease (16.7%). Lupus anticoagulant (7.1%) and anti-RNP (6.0%) were more represented in this group. Finally, in group 1, non-rheumatologic disease was the most represented group of disease. In the case of SLE and systemic sclerosis, there were no statistically significant differences between the three groups and the different types of organ involvement. In SS, sicca symptoms were more prevalent in group 2, with statistically significant differences between the groups (p=0.027). Table 1. Group 1 Ro52+/Ro60 - (n=107 ) Group 2 Ro52+/Ro60+ (n=86 ) Group 3 Ro52-/Ro60+ (n=84 ) p Immune-mediated rheumatologic diseases (n) 51 69 53 0.004 Systemic lupus erythematosus 10 16 7 0.396 Sjögren syndrome 21 40 20 0.050 Systemic sclerosis 2 1 2 0.618 Inflammatory myositis 4 0 1 0.024 Rheumatoid arthritis 9 2 7 0.020 Undifferentiated connective tissue disease 4 9 14 0.025 Other diseases 1 1 2 0.824 Non-rheumatologic disease (n) 56 17 31 0.369 Infections 3 1 2 0.978 Neoplasms 7 2 1 0.319 Liver cirrhosis 6 2 8 0.178 Interstitial lung disease 2 0 2 0.637 Chronic kidney disease 2 0 1 0.736 Unclassified 36 12 17 0.444 Conclusion In line with published studies, our work demonstrated that, among the sera tested, autoreactivity to anti-Ro52 alone was the most often observed and in most patients the presence of this antibody alone was not associated with immune-mediated rheumatologic disease, but mainly with malignancies. We also identified the clinical phenotype of patients with positive anti-Ro52 and/or anti-Ro60. Thus, we reinforce the importance of specific detection such as Ro-52 or Ro60 as they present individual diagnostic utility. References [1]Wu S et al. Int J Clin Pract. 2021 Mar;75(3):e13679. [2]Robbins A et al. Front Immunol. 2019 Mar 12;10:444. Disclosure of Interests None declared